Heat oven to 375 degrees F.,Boil chilies& onions until semi-tender and drain.,Coat 9x9" casserole with olive oil.,Spread croutons on bottom of casserole.,Spread chilies, onions and sausage over croutons.,______,Pour mixture over chilies and croutons.,Put casserole into preheated oven for 35-45 minutes.,Remove from oven and place tomato slices and sprinkle cheese on top; then bake again for 20 minutes.,Test with tip of sharp knife for doneness.,Cool 5 minutes and serve.,This casserole can be made with many other vegetables, such as eggplant, zucchini, summer squash, green beans, celery, etc.,If you're a vegan, just leave out the sausage.